
This implies the following properties of singular values (see, e.g., [1]}, [2]}),
\(\mu _j(T)=\mu _j(T^*)=\mu _j(|T|),\\\mu _{j+k}(S+T)\le \mu _j(S) + \mu _k(T),\\\mu _j(ATB)\le \Vert A\Vert  \mu _j(T) \Vert B\Vert ,\qquad A, B\in {L}({H}).\) 
